An efficient photoredox‐catalyzed halo‐trifluoromethylation reaction of 1,7‐enynes has been developed under mild conditions. This photocatalytic protocol provides an efficient and functional strategy leading to CF3− and halogen‐containing 3,4‐dihydroquinolin‐2(1H)‐ones from a wide range of 1,7‐enynes through two different radical pathways. The reaction mechanism was proposed based on the control experiments.magnified image

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Considering their unique roles in organic synthesis, and pharmaceutical and agrochemical applications, the development of fluoroalkylation, cyclization, and indole oxidative cleavage are important topics. Herein, an unprecedented electrochemical tri‐ and difluoromethylation/cyclization/indole oxidative cleavage process occurring in an undivided cell is presented. The protocol employs a readily prepared Langlois reagent as the fluoroalkyl source, affording a series of tri‐ or difluoromethylated 2‐(2‐acetylphenyl)isoquinoline‐1,3‐diones in good yields with excellent stereoselectivity. It is worth noting that this new methodology merges the fluoroalkylation/cyclization of N‐substituted acrylamide alkenes with the oxidative cleavage of an indole C(2)=C(3) bond under external oxidant‐free conditions.

A process for achieving photocatalyzed tri-and difluoromethylation/cyclizations for constructing a series of tri-or difluoromethylated indole[2,1-a]isoquinoline derivatives is described. This protocol utilized an inexpensive organic photoredox catalyst and provided good yields. Moreover, the combination of continuous flow and photochemistry, designed to provide researchers with a unique green process, was also shown to be key to allowing the reaction to proceed (product yield of 83% in flow vs 0% in batch).

A direct electrooxidative sulfonylation/heteroarylation reaction of alkenes with sulfinic acids, which proceeds through distal heteroaryl ipso-migration and C−S and C−C bond formations, is reported. This electro-synthetic method offers an efficient and environmentally friendly entry to prepare various sulfonated functionalized heteroarenes under an undivided cell at room temperature, avoiding the use of any metal catalysts, additives, and oxidants. Preliminary mechanistic studies indicated a radical pathway.